can anyone confirm what soil to plant it in, I'm putting it in an extremely large terracotta pot, from what I've read I don't quite understand what potting compost to get( or if to just use my own from my compost bin) as it seems to state they can go in different type soils. I read....They hate being too dry, so put lots of organic matter in the soil before planting and then mulch every year with a generous layer of compost.

The acid/alkaline things you've probably read are for the type which can have blue or pink flowers, depending on soil acidity. I think you should just use a well-balanced mix for yours, so stuff from your compost bin is probably ideal.